1. Field of the Invention
This invention relates to a chain transfer-regulated process for polymerizing polar, acrylic-type or maleimide monomers.
2. Background
U.S. Pat. Nos. 4,414,372; 4,417,034; 4,508,880; and 4,524,196 and U.S. patent application Ser. Nos. 701,681, filed Feb. 14, 1985 and allowed Feb. 21, 1986 and 707,193, filed Mar. 1, 1985 and issued May 13, 1986 as U.S. Pat. No. 4,588,795, hereinafter referred to as "the aforesaid patents", disclose processes for polymerizing certain polar monomers to "living" polymers. More specifically, the aforesaid patents disclose processes of polymerizing the monomer selected from the group consisting of CH.sub.2 .dbd.C(Y)X, ##STR1## and mixtures thereof wherein: X is --CN, --CH.dbd.CHC(O)X' or --C(O)X';
Y is --H, --CH.sub.3, --CN or --CO.sub.2 R, provided, however, when X is --CH.dbd.CHC(O)X', Y is --H or --CH.sub.3 ; PA1 X' is --OSi(R.sup.1).sub.3, --R, --OR or --NR'R"; PA1 each R.sup.1, independently, is a hydrocarbyl radical which is an aliphatic, alicyclic, aromatic or mixed aliphatic-aromatic radical containing up to 20 carbon atoms; PA1 R is a hydrocarbyl radical which is an aliphatic, alicyclic, aromatic or mixed aliphatic-aromatic radical containing up to 20 carbon atoms, optionally containing one or more ether oxygen atoms within aliphatic segments thereof and optionally containing one or more functional substituents that are unreactive under polymerizing conditions; and PA1 each of R' and R" is independently selected from C.sub.1-4 alkyl PA1 R.sup.1 is as defined above; PA1 Z is an activating substituent selected from the group consisting of ##STR2## and mixtures thereof wherein: X' is as defined above for the monomer; PA1 each of R.sup.2 and R.sup.3 is independently selected from H and hydrocarbyl, defined as for R above; PA1 Z' is O or NR', wherein R' is as defined above; PA1 m is 2, 3 or 4; PA1 n is 3, 4 or 5; and PA1 M is Si, Sn, or Ge, provided, however, when Z is ##STR3## M is Sn or Ge; and PA1 R.sup.1 and M are as defined above and Z.sup.1 is ##STR4## wherein X', R.sup.2 and R.sup.3 are as defined above; and/or PA1 M and R.sup.1 are as defined above; and PA1 Z.sup.2 is a diradical selected from the group consisting of ##STR5## and mixtures thereof, wherein R.sup.2, R.sup.3, X', Z', m and n are as defined above, provided, however, when Z.sup.2 is ##STR6## M is Sn or Ge; and/or PA1 wherein R, R.sup.1, R' and R" are as defined above; and/or PA1 X.sup.1 is ##STR15## provided however, when the monomer is a nitrile, X.sup.1 is ##STR16## each R.sup.4, independently, is C.sub.1-12 alkyl, C.sub.4-12 cycloalkyl, C.sub.6-12 aralkyl or di(C.sub.1-4 alkyl)amino, provided, however, two or three of the alkyl, cycloalkyl and/or aralkyl R.sup.4 groups may be joined together by means of one or more carbon carbon bonds, and provided, however, the alkyl, cycloalkyl and aralkyl groups may contain within aliphatic segments thereof one or more hetero atoms selected from O, N and S and one or more substituents that are unreactive under polymerizing conditions; and PA1 each R.sup.5 is --CH.sub.2 CH.sub.2 --, optionally containing one or more alkyl or other substituents that are unreactive under polymerizing conditions. PA1 R.sub.p is a radical, of valence p, which is the residue formed by removing at least one active hydrogen atom from a carbon acid having a pKa in the range 18&lt;pKa&lt;25 and having at least one active hydrogen atom attached to a carbon atom which is free of --CN and --C(O)X' substituents; PA1 p is an integer and is at least 1; PA1 P is a divalent polymer radical of the formula ##STR17## each of a and b is independently selected from 0 or a number in the range 1 to about 100,000, provided, however, (a+b) is at least 3; PA1 Q is the divalent radical selected from the group consisting of ##STR18## and mixtures thereof; X is --CN, --CH.dbd.CHC(O)X' or --C(O)X'; PA1 Y is --H, --CH.sub.3, --CN or --CO.sub.2 R, provided, however, when X is --CH.dbd.CHC(O)X', Y is --H or --CH.sub.3 ; PA1 X' is --OSi(R.sup.1).sub.3, --R, --OR or --NR'R"; PA1 each R.sup.1, independently, is a hydrocarbyl radical, which is an aliphatic, alicyclic, aromatic or mixed aliphatic-aromatic radical containing up to 20 carbon atoms, or H, provided that at least one R.sup.1 group is not H; PA1 R is a hydrocarbyl radical, which is an aliphatic, alicyclic, aromatic or mixed aliphatic-aromatic radical containing up to 20 carbon atoms, or a polymeric radical containing at least 20 carbon atoms, either radical optionally containing one or more ether oxygen atoms within aliphatic segments thereof and optionally containing one or more functional substituents that are unreactive under polymerizing conditions; PA1 each of R' and R" is independently selected from C.sub.1-4 alkyl; and PA1 M is Si, Sn or Ge.
by contacting the one or more monomers under polymerizing conditions with:
(i) the initiator of the formula (R.sup.1).sub.3 MZ wherein:
(ii) a co-catalyst which is a source of bifluoride ions HF.sub.2.sup.-, a source of fluoride, cyanide or azide ions, a suitable Lewis acid, for example, zinc chloride, bromide or iodide, boron trifluoride, alkylaluminum oxide or an alkylaluminum chloride, a suitable nonanionic Lewis base, or a source of oxyanions whose conjugate acids have a pKa in dimethylsulfoxide (DMSO) at 25.degree. C. of about 5 to about 24,
to produce "living" polymer having repeat units of the one or more monomers,
said process further characterized in that: .
(a) R.sup.1 is H, provided that at least one R.sup.1 group is not H; and/or
(b) R is a polymeric radical containing at least 20 carbon atoms and optionally containing one or more ether oxygen atoms within aliphatic segments thereof and optionally containing one or more functional substituents that are unreactive under polymerizing conditions; and/or
(c) at least one of any R group in the monomer contains one or more reactive substitutents of the formula --Z'(0)C--C(Y.sup.1).dbd.CH.sub.2 wherein Y.sup.1 is H or CH.sub.3 and Z' is as defined above; and/or
(d) the initiator is of the formula (R.sup.1).sub.2 M(Z.sup.1).sub.2 or O[M(R.sup.1).sub.2 Z.sup.1 ].sub.2 wherein
(e) at least one of any R, R.sup.2 and R.sup.3 in the initiator contains one or more initiating substitutents of the formula --Z.sup.2 --M(R.sup.1).sub.3 wherein
(f) Z is selected from the group consisting of --SR, --OP(NR'R").sub.2, --OP(OR.sup.1).sub.2, --OP[OSi(R.sup.1).sub.3 ].sub.2 and mixtures thereof,
(g) R.sup.2 and R.sup.3 taken together are ##STR7## provided, however, Z is and/or Z.sup.2 is ##STR8## and/or
(h) X' and either R.sup.2 or R.sup.3 taken together are ##STR9## provided, however, Z is ##STR10## and/or Z.sup.2 is ##STR11##
As further disclosed in the aforesaid patents, although these processes resemble anionic polymerization, there are significant differences which have commercial significance. These differences include the ability to copolymerize methacrylate and acrylate monomers, or combinations of acrylate monomers, for example, ethyl and sorbyl acrylates, to relatively monodisperse copolymers. Such copolymers are difficult or impossible to obtain by known processes such as anionic polymerization or free-radical polymerization. Moreover, whereas anionic polymerization processes which provide relatively monodisperse polymers are carried out at low temperatures, usually well below -10.degree. C., which require expensive refrigeration equipment for commercial operation, the polymerization processes of the patents are operable over a wide temperature range, from about -100.degree. C. to about 150.degree. C., and they are conveniently operable with many commercially important monomers at about ambient temperatures.
It is an object of this invention to provide a chain transfer-regulated modification of the processes disclosed in the aforesaid patents. A further object is to provide such a modification by means of which the molecular weight of the polymer produced can be controlled. Still another object is to provide chain transfer agents which are suitable in the processes of the aforesaid patents but which are inoperable in conventional art-recognized anionic processes for polymerizing the same type of monomer. These and other objects will be apparent from the disclosure which follows.